The novel pyrrolo-1,5-benzoxazepine, PBOX-15, synergistically enhances the apoptotic efficacy of imatinib in gastrointestinal stromal tumours; suggested mechanism of action of PBOX-15
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The C-KIT receptor tyrosine kinase is constitutively activated in the majority of gastrointestinal stromal tumours (GIST). Imatinib (IM) a selective inhibitor of C-KIT, is indicated for the treatment of KIT-positive unresectable and/or metastatic GIST, and has tripled the survival time of patients with metastatic GIST. However, the majority of patients develop IM-resistance and progress. Although IM elicits strong antiproliferative effects, it fails to induce sufficient levels of apoptosis; acquired IM-resistance and disease recurrence remain an issue, a more effective drug treatment is greatly needed. We examined the effect of a novel microtubule-targeting agent (MTA), pyrrolo-1,5-benzoxazepine (PBOX)-15 in combination with IM on GIST cells. PBOX-15 decreased viability and in combination with IM synergistically enhanced apoptosis in both IM-sensitive and IM-resistant GIST cells, decreased the anti-apoptotic protein Mcl-1, and enhanced activation of pro-caspase-3 and PARP cleavage. The combination treatment also led to an enhanced inhibition of C-KIT-phosphorylation and inactivation of C-KIT-dependent signalling in comparison to either drug alone; CDC37, a key regulator of C-KIT in GIST was also dramatically decreased. Furthermore, PBOX-15 reduced CKII expression, an enzyme which regulates the expression of CDC37. In conclusion, our findings indicate the potential of PBOX-15 to improve the apoptotic response of IM in GIST cells and provide a more effective treatment option for GIST patients.
KeywordsGastrointestinal Imatinib Microtubules CKIT CDC37 CKII
We would like to thank Novartis Pharma AG, Basel, Switzerland for their kind donation of imatinib. We would also like to thank Dr. Jonathan Fletcher for his initial advice with this project.
Compliance with ethical standards
Conflict of interest
The authors declare that they have no conflict of interest.
- 1.Heinrich MC, Corless CL, Demetri GD, Blanke CD, von Mehren M, Joensuu H, McGreevey LS, Chen CJ, Van den Abbeele AD, Druker BJ, Kiese B, Eisenberg B, Roberts PJ, Singer S, Fletcher CD, Silberman S, Dimitrijevic S, Fletcher JA (2003) Kinase mutations and imatinib response in patients with metastatic gastrointestinal stromal tumor. J Clin Oncol 21:4342–4349CrossRefPubMedGoogle Scholar
- 2.Hirota S, Isozaki K, Moriyama Y, Hashimoto K, Nishida T, Ishiguro S, Kawano K, Hanada M, Kurata A, Takeda M, Muhammad Tunio G, Matsuzawa Y, Kanakura Y, Shinomura Y, Kitamura Y (1998) Gain-of-function mutations of c-kit in human gastrointestinal stromal tumors. Science 279:577–580CrossRefPubMedGoogle Scholar
- 5.Lennon JC, Bright SA, Carroll E, Butini S, Campiani G, O'Meara A, Williams DC, Zisterer DM (2014) The novel pyrrolo-1,5-benzoxazepine, PBOX-6, synergistically enhances the apoptotic effects of carboplatin in drug sensitive and multidrug resistant neuroblastoma cells. Biochem Pharmacol 87:611–624CrossRefPubMedGoogle Scholar
- 7.Nathwani SM, Butler S, Fayne D, McGovern NN, Sarkadi B, Meegan MJ, Lloyd DG, Campiani G, Lawler M, Williams DC, Zisterer DM (2010) Novel microtubule-targeting agents, pyrrolo-1,5-benzoxazepines, induce apoptosis in multi-drug-resistant cancer cells. Cancer Chemother Pharmacol 66:585–596CrossRefPubMedGoogle Scholar
- 8.McElligott AM, Maginn EN, Greene LM, McGuckin S, Hayat A, Browne PV, Butini S, Campiani G, Catherwood MA, Vandenberghe E, Williams DC, Zisterer DM, Lawler M (2009) The novel tubulin-targeting agent pyrrolo-1,5-benzoxazepine-15 induces apoptosis in poor prognostic subgroups of chronic lymphocytic leukemia. Cancer Res 69:8366–8375CrossRefPubMedGoogle Scholar
- 9.Bright SA, McElligott AM, O'Connell JW, O'Connor L, Carroll P, Campiani G, Deininger MW, Conneally E, Lawler M, Williams DC, Zisterer DM (2010) Novel pyrrolo-1,5-benzoxazepine compounds display significant activity against resistant chronic myeloid leukaemia cells in vitro, in ex vivo patient samples and in vivo. Br J Cancer 102:1474–1482CrossRefPubMedPubMedCentralGoogle Scholar
- 10.Garner AP, Gozgit JM, Anjum R, Vodala S, Schrock A, Zhou T, Serrano C, Eilers G, Zhu M, Ketzer J, Wardwell S, Ning Y, Song Y, Kohlmann A, Wang F, Clackson T, Heinrich MC, Fletcher JA, Bauer S, Rivera VM (2014) Ponatinib inhibits polyclonal drug-resistant KIT oncoproteins and shows therapeutic potential in heavily pretreated gastrointestinal stromal tumor (GIST) patients. Clin Cancer Res 20:5745–5755CrossRefPubMedPubMedCentralGoogle Scholar
- 11.Campiani G, Nacci V, Fiorini I, De Filippis MP, Garofalo A, Ciani SM, Greco G, Novellino E, Williams DC, Zisterer DM, Woods MJ, Mihai C, Manzoni C, Mennini T (1996) Synthesis, biological activity, and SARs of pyrrolobenzoxazepine derivatives, a new class of specific "peripheral-type" benzodiazepine receptor ligands. J Med Chem 39:3435–3450CrossRefPubMedGoogle Scholar
- 14.Gupta A, Roy S, Lazar AJ, Wang WL, McAuliffe JC, Reynoso D, McMahon J, Taguchi T, Floris G, Debiec-Rychter M, Schoffski P, Trent JA, Debnath J, Rubin BP (2010) Autophagy inhibition and antimalarials promote cell death in gastrointestinal stromal tumor (GIST). Proc Natl Acad Sci U S A 107:14333–14338CrossRefPubMedPubMedCentralGoogle Scholar
- 15.Nagata K, Kawakami T, Kurata Y, Kimura Y, Suzuki Y, Nagata T, Sakuma Y, Miyagi Y, Hirano H (2015) Augmentation of multiple protein kinase activities associated with secondary imatinib resistance in gastrointestinal stromal tumors as revealed by quantitative phosphoproteome analysis. J Proteome 115:132–142CrossRefGoogle Scholar
- 16.Greene LM, Kelly L, Onnis V, Campiani G, Lawler M, Williams DC, Zisterer DM (2007) STI-571 (imatinib mesylate) enhances the apoptotic efficacy of pyrrolo-1,5-benzoxazepine-6, a novel microtubule-targeting agent, in both STI-571-sensitive and -resistant bcr-abl-positive human chronic myeloid leukemia cells. J Pharmacol Exp Ther 321:288–297CrossRefPubMedGoogle Scholar
- 17.Marino-Enriquez A, Ou WB, Cowley G, Luo B, Jonker AH, Mayeda M, Okamoto M, Eilers G, Czaplinski JT, Sicinska E, Wang Y, Taguchi T, Demetri GD, Root DE, Fletcher JA (2014) Genome-wide functional screening identifies CDC37 as a crucial HSP90-cofactor for KIT oncogenic expression in gastrointestinal stromal tumors. Oncogene 33:1872–1876CrossRefPubMedPubMedCentralGoogle Scholar
- 18.Kim SJ, Uehara H, Yazici S, Langley RR, He J, Tsan R, Fan D, Killion JJ, Fidler IJ (2004) Simultaneous blockade of platelet-derived growth factor-receptor and epidermal growth factor-receptor signaling and systemic administration of paclitaxel as therapy for human prostate cancer metastasis in bone of nude mice. Cancer Res 64:4201–4208CrossRefPubMedGoogle Scholar
- 22.Quattrone, A., A. Wozniak, B. Dewaele, G. Floris, V. Vanspauwen, T. Van Looy, P. Schoffski, P. Rutkowski, R. Sciot, and M. Debiec-Rychter (2014) Frequent mono-allelic loss associated with deficient PTEN expression in imatinib-resistant gastrointestinal stromal tumors. Mod PatholGoogle Scholar
- 26.Sarno S, Ghisellini P, Pinna LA (2002) Unique activation mechanism of protein kinase CK2. The N-Terminal Segment Is Essential for Constitutive Activity of the Catalytic Subunit but not of the Holoenzyme J Biol Chem 277:22509–22514Google Scholar